9. a2a3 There's a small detail White has to keep in mind when choosing this instead of 9.exd4. In 1999, I played 9.a3 with White and thought I was very clever doing so, but fifteen minutes later, I wasn't sure anymore. Actually, I'm still not sure about it 25 years later. 9... b4e7  10. e3d4  10... d8c7 I didn't know this move. I used to play 10...d6, when White is slightly better but it's not a big deal. 11. f1e1 This prevents 11...Ng4, which can simply be answered by 12.h3, but allows Black to play 11...d5.